The only comparative study of the inclusive pion single-spin asymmetries produced in the interactions of the polarized protons and antiprotons in collisions with unpolarized proton was carried out at E-704 experiment. Significant asymmetries were found at large $x_{ F}$ and middle $p_{ T}$, $\pi^{ +}$ and $\pi^{ 0}$ asymmetries have positive signs while $\pi^{ -}$ has negative one in the $p^{ \uparrow}+p$ collisions, while in the $\bar{ p}^{ \uparrow}+p$ interactions the $\pi^{ -}$ and $\pi^{ 0}$ asymmetries have positive signs while $\pi^{ +}$ has negative sign. Similar experimental study can be done in the SPASCHARM experiment at U-70 accelerator at IHEP for various secondary particles with the use of 16 GeV polarized proton and antiproton beams.
Categories: hep-ex nucl-ex